How Loud is Loud ??

April 15, 2009

You’ve heard of a “decibel” as a description of a unit of sound but did you realise that the “bel” bit of the phrase comes from Alexander Graham Bell…one of the pioneers of the Telephone ?? They needed a scale (Bel) to measure how the volume of sound degraded over different/longer lengths of telephone cable. As the sound pressure of a Jet engine is 10 million times stronger/louder than virtual silence the decibel (dB) system is used to make the Bel scale more manageable. This gives a range of 0 to 140 which is the average level of sound a human being would normally ever be exposed to.

I’ve visited the Rolls Royce jet engine test facility and stood next to a speaker at an Iggy and the Stooges concert and after both experiences my head was still ringing two days later. These days I prefer the 10dB sound pressure level of rustling leaves !!